To maintain costs as low as possible, EP printers are designed to allow as much user maintenance as possible. EP printers which employ liquid toners are provided with refillable toner reservoirs and require the user to replenish the in-printer reservoir from a liquid toner supply. The user is thus exposed to possible spillage, and, with color printers, a possibility that a wrong color toner may be loaded into a reservoir. To prevent such a possibility, EP printers are now designed to accommodate user-replaceable liquid toner cartridges. To accommodate such a replaceable toner cartridges, an interconnect must be provided that enables the cartridge to be easily and reliably replaced, while not allowing toner leakage that can escape beyond the confines of the printer and contaminate the user or his/her environment.
In FIG. 1, a prior art "low-spillage" quick disconnect is illustrated in a disconnected form. A male fitting 10 is integral to an inlet port of an EP printer and is adapted to receive liquid toner from a female fitting 12 which forms a portion of a liquid toner cartridge. Male fitting 10 comprises an inlet housing 14 which includes a hollow interior section 16 that communicates with a toner inlet to the printer (not shown). A plurality of struts 18 (only one is shown in FIG. 1) support a fixed plunger 20 which includes an inverted conical portion 22. An O-ring 24 is inset into the surface of inverted conical portion 22 and enables a sealing action between inverted conical portion 22 and a mating terminal end of a slidable sleeve 26. A further spring 28 seals the outer diameter of slidable sleeve 26 to housing 14. A spring 30 biases slidable sleeve 26 against an inwardly disposed ledge 32 of housing 14.
Female fitting 12 comprises an outer housing 34 which contains a slidable plug member 36. One end of slidable plug member 36 is sealed to housing 34 by an O-ring 38. A spring 40 biases slidable plug member 36 against a reduced internal diameter ledge 37 within housing 12 and provides a sealing action until slidable plug member 36 is moved rightwardly by action of male fitting 10. An inlet opening 42 communicates with the interior of a liquid toner cartridge and enables delivery of liquid toner into the interior of housing 34 and through outlet tube 44 within slidable plug member 36. When slidable plug member 36 is displaced to the right, outlet tube 44 is enabled to feed toner liquid through a left-most outlet orifice 46 in housing 34.
In FIG. 2, the configuration of male fitting 10 an female fitting 12 is illustrated after interconnection. It can be seen that, initially, inverted conical portion 22 of plunger 20 contacts the outermost portion of slidable plug 36 and begins to move it in a rightward direction, thereby compressing spring 40. At the same time, slidable sleeve 26 enters opening 46 in housing 34 and is stopped from further penetration thereinto by the interaction of a shoulder 47 on the exterior thereof with the edge of opening 46. As a result, slidable sleeve 26 is moved in a leftward direction, causing spring 30 to be compressed and opening a pathway for liquid toner to pass from tube 44 and into the interior of housing 14 (and from thence into a connected printer).
As can be seen from the above, the prior art low spillage quick disconnect mechanism includes many parts and plural sliding O-ring seals which can become contaminated with dried toner, etc. In such case, sliding sleeve 26 can become stuck in a "open" position thereby enabling toner to leak from male fitting 10.
Accordingly, it is an object of this invention to provide an improved low-spillage, quick disconnect fitting for providing liquid toner to an EP printer.
It is another object of this invention to provide a low-spillage quick disconnect fitting of reduced complexity.
It is another object of this invention to provide an improved low-spillage quick disconnect fitting which has an ability to tolerate misalignment of connector halves.